Out look Error

When ever I try to open my outlook the following error is showing Pls help me to solve this

"cannot start Microsoft outlook Cannot open the outlook window the set of folders cannot be opened an unexpected error has occurred MAPI was unable to load the information service nwnsp.dll be sure the service is correctly installed and configured."

On the next window show this error code

OLEAUT32.dll

How can I confg. the out look to my company email now I using lotus notes but its very slow thatsy I trying outlook
Pls help me to slove the issue